An elastomer composition obtained by irradiating electron beams to a thermoplastic elastomer composition including an electron beam cross-linking type thermoplastic resin, as a matrix, in which electron beam degradation type thermoplastic resin particles are discontinuously dispersed in it, as a dispersed phase, is known in the art (see Japanese Patent No. 3236247). A technology of irradiating electron beams to a syndiotactic polypropylene composition for the purpose of maintaining the flexibility and heat resistance is also known in the art (see Japanese Patent Publication (A) No. 2000-344975).